On Thu, Apr 11, 2024 at 10:59 PM David Gow davidgow@google.com wrote:
KUnit's try-catch infrastructure now uses vfork_done, which is always set to a valid completion when a kthread is created, but which is set to NULL once the thread terminates. This creates a race condition, where the kthread exits before we can wait on it.
Keep a copy of vfork_done, which is taken before we wake_up_process() and so valid, and wait on that instead.
Fixes: 4de2a8e4cca4 ("kunit: Handle test faults") Reported-by: Linux Kernel Functional Testing lkft@linaro.org Closes: https://lore.kernel.org/lkml/20240410102710.35911-1-naresh.kamboju@linaro.or... Tested-by: Linux Kernel Functional Testing lkft@linaro.org Acked-by: Mickaël Salaün mic@digikod.net Signed-off-by: David Gow davidgow@google.com
Hello,
This fix looks good to me. I have tested it and besides the fortify test error discussed in the previous patch series I am happy.
Thanks! -Rae
Reviewed-by: Rae Moar rmoar@google.com
lib/kunit/try-catch.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c index fa687278ccc9..6bbe0025b079 100644 --- a/lib/kunit/try-catch.c +++ b/lib/kunit/try-catch.c @@ -63,6 +63,7 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) { struct kunit *test = try_catch->test; struct task_struct *task_struct;
struct completion *task_done; int exit_code, time_remaining; try_catch->context = context;@@ -75,13 +76,16 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) return; } get_task_struct(task_struct);
wake_up_process(task_struct); /* * As for a vfork(2), task_struct->vfork_done (pointing to the * underlying kthread->exited) can be used to wait for the end of a* kernel thread.
* kernel thread. It is set to NULL when the thread exits, so we* keep a copy here. */
time_remaining = wait_for_completion_timeout(task_struct->vfork_done,
task_done = task_struct->vfork_done;wake_up_process(task_struct);time_remaining = wait_for_completion_timeout(task_done, kunit_test_timeout()); if (time_remaining == 0) { try_catch->try_result = -ETIMEDOUT;-- 2.44.0.683.g7961c838ac-goog